Hydraulic drive



July 25, 1933. F. WALTHER HYDRAULIC DRIVE Filed on. 24, 1931 fig 3.

Zwl/nff. 2114 M22 filer T252 Patented July 25, 1933 NITED STATES'YPATENT OFFICE FRITZ WALTHER, OF PLAUEH, GERMANY HYDRAULIC DRITTE Application filed October 24, 1931, Serial No. 570,940, and in Germany August 19, 1930.

This invention relates to a hydraulic drive for the adjustable parts of machine tools and the like. v

In hydraulic control devices for the adjustable parts of machine tools and the llke provision has been made hitherto only for a reversal of the pressure oil-delivery device in the limiting positions of the machine parts to be moved. It has not been possible till now to vary the speed of the machine parts to be adjusted during the working stroke. In order to attain this object the invention provides that the pressure medium be delivered by a, pump of 1 known type, the delivery of which can be regulated by adjusting a link which is adjusted by means of curved paths secured to the machine part to be adjusted in such a way that the link is held up at various points during the forward and return motion of the machine part to be adjusted at various positions and the speed of the part concerned can thus be determined at the various points in a regulatable manner by the form of the curved paths.

One form of the invention is illustrated in the accompanying drawing. Q

Figure 1 shows the entire arrangement of the control device of a'machine tool 80 partly in side view and partly in section.

Figure 2 is an axial section of the two stage pump.

Figure 3- is a side view showing the arrangement of two slides side by side for controlling the forward and return motion of the ,machine part to be adjusted.

Figure 4 is a side view partly in section showing the manner of reversin of a cam.

Referring to the drawing: 0 the machine frame 1 the guide case 2 for the link 3 of the high pressure part of the pump is secured which has an annular recess 4 on the wall of which the pressure rolls 6.arranged on the pump pistons 5 rotate. The pistons 5 are disposed axially displaceably in the rotary pump body 7 which revolves about the axle-journal 8 provided in the known manner with conduits for the suppl and discharge of the pressure medium wich enters the passing guide sleeves of the pistons 5 during the first half rotation of the pump body 7 and is pressed into the other conduit during the second half, the amount of pressure liquid taken out of the supply conduit and pressed into the discharge conduit depending on the extent to which the pistons 5 travel to and fro in their guides of the pum body 7. The amount is controlled by a justing the link 3 moved for this purpose b .means of the connecting rod 9 and the t ree-armed adjusting lever 10, 11, 12 rotatably arranged on the frame 1 by meansof the bolt 13. The arm 10 is engaged by the connecting rod 9, and to the arm 11 the coupling rod 14 is articulated, the other end of which has the thread 15 which engages the female thread of the adjusting sleeve 16. The sleeve 16 is rotatably and axially displaceably disposed in the machine frame 1 and provided with the flange 17 which, under the circumstances explained in the following, can rest on the frame 1 to permit adjustment of the rod 14 and thus of the threearmed lever 10, 11, 12 and the link 3 by turningl the sleeve 16. In order to determine t e position of the rod 14, it carries the'rack acting worm 18 which engages the pinion 19 which in turn engages the helical gear 20 whose shaft is arranged on the 89 frame 1 and sets a pointer 21 on the outside thereof.

The lever 12 engages a slide 22 vertically adjustable relative to the guide sleeve 23 secured to the frame 1. The upper end of the slide 22, by means of the bolt 24, carries two table reversing dogs 25 and 26, each of which hugs with one side the wall portion 27 of the slide 22 under the urge of the spring 28. The do 25, according to Fig. 4, is reversible towards the side of the spring 28 if the table is displaced in the direction of the arrow 29. If the table moves in the opposite direction, the dog 25 will abut" against the wall' portion 27 of the slide 22 to permit transmission from the cam 32 secured to the reciprocating table 31 to the slide 22. The dog 26 is similarly disposed as the dog 25, but reversible in a direction opposite to-that of the latter and thus acting I begins.

in a diflerent direction from that of the latter during a displacement of the tool table 31. In this manner it becomes possible to render one or the other do efi'ective during the reciprocatory motion 0 the table or carriage 31 and to attach difierent cams 32 for the control of the forward and return motion of the table 31 to the latter.

In order to transmit motion as free from friction as possible each of the dogs 25 and 26 is preferably provided with a roll 33.

In the adjustment of the slide 22, the three-armed lever 10, 11, 12 and the link 3 is eifected by the cams 32 of the machine tool table 31, the rod 14, during its reciprocatory motions, has enough play to drive the sleeve 16 .without being handicapped thereby in its motion, provided the sleeve 16 has been returned to its initial position indicated by the pointer 21 before the automatic control of the pump stroke by the cam 32 When the cams 32 are unscrewed from the table 31, hand control of the stroke is possible by means of the sleeve 16.

The pump is of the two stage type. The low pressure part comprises a wheel pump 34-, 35, the portion 35 being firmly connect ed with a lateral projection of the pump body 7 constructed as a hollow shaft, and cooperating in the motion of the body 7 driven by means of the spur gear 36. The amount of pressure medium delivered by the low pressure pump 34, 35 serves for returning the table 31, and a part of the quantity thus delivered passes'into the high pressure part consisting of the pump body 7 and the piston 5 radially displaceable therein. Under the influence of the pressure medium the link 3 will always move in the direction of that side of the high pressure pump where the discharge of the pressure medium delivered takes place, that is, according to the drawing, to the right. Thus, during hand control, the collar 17 will be kept in contact with the machine frame 1 and, duringautomatic control, the slide 22, by means of the roll 33, in contact with the cams 32.

I claim ulatably determining the speed of the machine part, a slide vertically adjustable to the said sleeve, l-two oppositely reversible dogs attached to the top part of the said slide and adapted to alternately eficct trans mission of motion from a cam secured to the machine part to be adjusted to the said slide, stops for holding the said dogs in position, and means connecting the said slide with the adjustable link, the adjustment of the link tor the forward and return motion of the machine part being effected by diiferen t cams independently of one another.

2. A hydraulic drive for the adjustable parts of machine tools, comprising a pump adapted to deliver a pressure medium, a guide sleeve, an adjustable link cooperating with said sleeve and adapted to regulate the delivery of said pump, cams connected to the machine part to be adjusted, means connecting said link with the cams, said means holding the link in predetermined positions during the forward and return motion of the machine part, a slide vertically adjustable ,to the said sleeve, oppositely reversible dogs attached to the top part of said slide and adapted to alternately effect transmission of motion from the cams, stops for holding said dogs in position, and means connecting said slide with the ad ustable link, the adjustment of the link for the forward and return motion of the machine part being effected by different cams independent of each other.

FRITZ WALTHER. 

